The living database

A software engineer looks at God’s blueprint for a human being

I am a software engineer by profession (i.e. a ‘computer geek’), so
perhaps it is inevitable that I would look at the human body from an information-processing
point of view.

When a new human being is conceived, he or she consists of only one tiny microscopic
cell. How does that single cell grow into a complete body? As that one cell becomes
many, how does each one ‘know’ whether it is supposed to be bones, or
skin, or parts of the eye or lung or heart, all arranged in the correct places?

As with any building project, the first essential step is to have a plan, a blueprint.
For a human being, this blueprint is called the ‘genome’. Every cell
in your body has a copy of this blueprint, ‘written’ on the long chain
molecule called DNA (deoxyribonucleic acid)
that makes up your chromosomes.

Only in the last half of the 20th century have we begun to understand
this blueprint. Before then, people could only guess that such even existed.

What biologists have learned so far displays what software engineers would call
amazingly ‘elegant’ design.

At the lowest level, the genome is built from just four different chemicals, called
‘bases’ (adenine, thymine, cytosine, and guanine), chemically bound
to a molecular backbone. These bases are combined into groups of three, called ‘codons’.
Codons are combined into groups of various length called ‘genes’. The
average gene has about a 1,000 codons. Genes of related function are often grouped,
together with genes that control whether they are active or not, into ‘operons’.
Operons are combined into chromosomes. And all the chromosomes make up the genome.
The entire human genome includes about one billion codons, or three billion bases.

Notice how similar this organization is to a written language. A base is like a
letter. A codon is like a word, a gene like a sentence. An operon can perhaps be
likened to a paragraph, and a chromosome is like a chapter. And the genome would
then be the entire book.

Actually reading this ‘book’ is another matter. By studying chromosomes
under a microscope, a skilled technician can tell a few basic things about the person
they came from, like whether this person is male or female — one of the chromosomes
looks distinctly different. It is also possible to recognize some types of birth
defects. For example, Down’s syndrome can be recognized by a certain extra
chromosome.

But until recently, that was about it. It was like someone who had lost his glasses
trying to read a book: he might be able to tell how long the chapters are, or notice
that a page was torn out, but that was all.

In recent years biologists have learned to read the ‘letters’. That
is, with much high tech equipment and sophisticated techniques, they can find exactly
which bases make up almost any given section of the genome. The ‘book’
is so long that it’s taken years to (almost) decipher with the help of supercomputers.
But for the most part, it’s like reading a book written in a foreign language;
just knowing the alphabet isn’t enough.

We do understand the function of one important part of the human genome: some sections
control the manufacture of proteins. Proteins are key chemicals in your body, made
of smaller pieces called amino acids; often thousands of them, strung together in
a long chain. This then folds to make the protein.

There are 20 amino acids, and the sequence in which they are assembled determines
the structure and function of the resultant protein. A gene is that stretch of DNA
coding for one particular protein, with each of the codons in that gene coding for
one amino acid.

This only accounts for a small percentage of the human genome. The figure given
varies, but evolutionists generally say that the remainder, 90% or so, must therefore
be left-overs (‘junk’ DNA) from earlier stages of evolution, no longer
used or needed. But this is an argument based on ignorance: ‘We don’t
know what its purpose is, therefore it has no purpose.’ It would seem more
reasonable to withhold judgment until there has been more research, especially considering
that it is only in the last few years that we have begun to understand the function
of the protein-making sections.

There are plenty of parts in my car that I don’t understand. But I do not
therefore conclude that they are useless leftovers from an earlier era in automobile
design, carelessly included despite no longer having any purpose.1

Computer experts often strive for what we call an ‘elegant’ design.
By that we mean a system which solves a complex problem, but which at heart is simple
and consistent. The ideal design uses the fewest different pieces, and combines
them in consistent ways.

Look at the elegance of the genome. At the lowest level, there are only four different
bases. These are always combined in groups of three. Never two, never four, always
three.

But why three bases in a codon, you might ask? What’s special about
that number? Well, there are 20 different amino acids in human proteins. One base
to specify each amino acid would not be enough; there are only four different bases,
but 20 amino acids. Two would give 4 x 4 = 16 possibilities, still not quite enough.
Three is enough: 4 x 4 x 4 = 64, which of course is more than 20.2 Four
would have been overkill, far more possibilities than necessary.

And of all the billion billion possible ways that 64 codons could code for 20 amino
acids, ours turns out to be among the very best (see DNA below).

In short, this is exactly the sort of design that a computer expert would admire.
A minimal number of different pieces to keep it simple, combined into groups of
exactly the right size to be just enough to express the desired information with
no waste, and with a consistent method of interpreting the data.

Could such a system have arisen by chance? The scheme is so neat and tidy. Random
processes rarely result in neatness. Few computer systems designed by experts display
as much elegance and sophistication as we find in the human genome.

How much information is in the human genome? If we were to type it out, one letter
for each of one person’s three billion bases, it would take 500,000 pages
— single-spaced, both sides of the paper. Stored on a computer, using one
byte (the amount for storing a letter or digit of text) per base, we would need
three billion bytes, or three ‘gigabytes’. As little as five or six
years ago, only the largest computers could handle this much data. And actually
doing anything with this amount of information is another story. The most complex
computer programs written today — compilers, the programs used to write other
programs — now require as much as 150 million bytes. This is about one twentieth
of the amount of information in the human genome — i.e. in each cell.

In short, it is just within the last few years that human beings have reached the
point where we can even hope to process the amount of information that is contained
in a human genome. Our most sophisticated ‘machines’—computer
software—are just now reaching the same scale.

DNA is vastly more efficient at storing information than is our present technology.
In the amount of DNA which would fill a pinhead, one could store the information
which, typed out, would make a pile of paperback-size pages so high that it would
reach from here to the moon 500 times!3

It is perhaps possible that people alive now may live to see the day when human
beings will create a code as sophisticated as the blueprint for a human body. However,
our body is much more than a code. The blueprint is only expressed within an existing
cell which has all the machinery to manufacture the proteins and other components
specified by the code. Constructing even a single cell ‘from scratch’
would be a very, very tall order.

If mankind ever achieves such a feat, it would just underline the incredible intelligence
of our wonderful Creator God, who created all kinds of living things in just a few
days during Creation Week.

DNA’s chosen language … an evolutionary conundrum.

Evolutionists have often pondered the ‘why’ of the actual DNA code,
the ‘language convention’ universal to all living things, which prescribes
which triplet codon specifies which amino acid. There are many other possible conventions
which could have been used, but it has now been discovered that the existing one
‘resists error better than a million other possible codes’.1

Such incredible error-proof efficiency should shout ‘design’ to them,
but instead they see it as evidence that the choice of code must have been shaped
by natural selection, i.e. approaching its current perfection by trial and error.

But herein is a conundrum for them. As some have pointed out, once there was an
existing language convention, no matter how error-prone, any subsequent changes
by chance would have been ‘like switching the keys on a typewriter, leading
to hopelessly garbled proteins’.1 Thus, however the code began
is how it would have stayed. In the evolutionary scenario, that means that a random
origin just ‘happened’ to fluke odds of a million or so to one to arrive
at the best possible code. This is good evidence against evolution — the code
convention is clearly the result of deliberate, creative design.

Reference

Tracking the History of the Genetic Code, Science281:329-331,
July 17, 1998.

The chicken or the egg?

The complex mechanisms needed to decode the DNA, and to proof-read it for errors
are themselves proteins, coded in the DNA. Thus we have the classic chicken and
egg problem: since proteins are needed to read, check and manufacture DNA, and DNA
is needed to make proteins, which came first in the alleged evolutionary process?

The obvious answer is that they did not evolve, but were created together. Some
have tried to suggest that originally, something like RNA (a chemical related to
DNA) was able to be both code and replicator, i.e. chicken and egg. But there are
huge problems with this and related suggestions:

References and notes

Mutations in non-coding DNA have been found to cause cancer, which suggests that
this DNA is very important.

The extra codes are not wasted. There is more than one code for different amino
acids. The extra codes make the system robust so that mutations (copying errors
during reproduction) which change one base are less likely to change the amino acid
coded for.